• Title/Summary/Keyword: Communication Jamming

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Adaptive Decoding Scheme of Concatenated Codes for Frequency-Hopped Spread-Spectrum Communications with a Pulse-Burst Jamming (펄스형 Jamming 신호가 존재하는 주파수 도약 대역확산 통신환경에서 쇄상부호 시스템의 적응 복호화 방식)

  • 김정곤;김성대;김형명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.7
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    • pp.1234-1243
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    • 1994
  • We propose an adaptive decoding scheme for a concatenated codes with frequency-hopped spread-spectrum communication system in the presence of a pulse-burst jammer and its performance is analyzed. Concatenated coding system employing binary inner code and Reed-Solomon outer code is investigated and the use of side information is allowed to decode both erasures and errors. Our scheme makes the decoder adapts to the level of jamming by switching between two decoding modes such that the overall block error probability can be reduced. It is shown that the proposed decoding scheme yields a significant performance improvement over a conventional decoding scheme.

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Secrecy Performance of Multi-Antenna Satellite-Terrestrial Relay Networks with Jamming in the Presence of Spatial Eavesdroppers

  • Wang, Xiaoqi;Hou, Zheng;Zhang, Hanwei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3152-3171
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    • 2022
  • This work investigates the physical layer secrecy of a multi-antenna hybrid satellite-terrestrial relay networks (HSTRN) with jamming, in which a satellite aims to make communication with a destination user by means of a relay, along with spatially random eavesdroppers. In order to weaken the signals of eavesdroppers, the conventional relay can also generate intentional interference, besides forwarding the received signal. Shadowed-Rician fading is adopted in satellite link, while Rayleigh fading is adopted in terrestrial link, eavesdropper link and jamming link. The analytical and asymptotic formulas for the system secrecy outage probability (SOP) are characterized. Practical insights on the diversity order of the network are revealed according to the asymptotic behavior of SOP at high signal-to-noise ratio (SNR) regime. Then, analysis of the system throughput is examined to assess the secrecy performance. In the end, numerical simulation results are presented to validate the theoretical analysis and point out: (1) The secrecy performance of the considered network is affected by the channel fading scenario, the system configuration; (2) Decrease of the relay coverage airspace can provide better SOP performance; (3) Jamming from the relay can improve secrecy performance without additional network resources.

Vulnerabilities and Attack Methods in Visible Light Communications Channel (가시광 통신 채널의 취약성 및 공격 방법)

  • Park, So-Hyun;Joo, Soyoung;Lee, Il-Gu
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.10a
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    • pp.469-471
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    • 2021
  • As wireless communication technology advances to ensure high accuracy and safety at high speeds, research and development of Visible Light Communication (VLC) technology has been accelerated as an alternative to traditional radio frequency (RF) technology. As the radio spectrum of RF communication becomes more congested and demand for bandwidth continues to increase, VLCs that can use unlicensed frequency band are proposed as a solution. However, VLC channels have broadcasting characteristics that make them easily exposed to eavesdropping and jamming attacks, and are vulnerable to MITM (Man-In-The-Middle) due to their line of sight (LOS) propagation characteristics. These attacks on VLC channels compromise the confidentiality, integrity, and availability of communications links and data, resulting in higher data retransmission rates, reducing throughput and increasing power consumption, resulting in lower data transmission efficiency. In this work, we model vulnerable VLC channels to analyze the impact of attacks and communications vulnerabilities by malicious jammers.

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Adaptive Projection Matrix Beamformer for Frequency Hopping Systems Robust to Jamming environment (의도적 간접신호에 강한 주파수 도약 시스템용 적응 투영행렬 빔형성 기법)

  • Jung, Sung-Hun;Shim, Sei-Joon;Kim, Sang-Heon;Lee, Chung-Yong;Youn, Dae-Hee
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.8 s.338
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    • pp.25-32
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    • 2005
  • Frequency hopping system has been adopted to many communication systems in order to overcome the inferior situation such as jamming environment. But typically its processing gain being limited, data interfered by jamming signal could not be fully recovered. This can be enhanced by combing FH system with spatial interference canceller which is a kind of active beamformer In this Paper, we proposed the compensation method of weight vector discrepancy according to the hopped frequencies and the PMBF method which is able to eliminate the inference effectively with less computational complexity. That is, the steering vector of wanted signals can be calculated from the frame without jamming signals using eigen analysis. New projection matrix extracted by the steering vector of wanted signal eliminates the interferences from the covariance matrix of received signal including wanted signal and jamming signals. This PMBF has similar performance of SINR beamformer with less computational complexity.

Analysis of Anti-jamming for GPS Guided Missile by GPS Reception Azimuth Control (GPS 수신 방위각 제어를 통한 GPS 유도무기 재밍대응 분석)

  • Choi, Chang-Mook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.3
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    • pp.677-682
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    • 2016
  • Recently, because Global Positioning System (GPS) achieves accuracy for engagement of enemy targets, GPS guided weapons have a wide range of applications from land through sea to air. Especially, when GPS guided weapon is then launched, it reads current position and searches a course to the target. As we all know, because GPS signals are weak, these signals can be affected by interference. If jamming signal is strong enough, it can jam the receiver of GPS guided weapon. Therefore, anti-jamming technique is an important thing under these conditions. In this paper, the controlling azimuth angle was used to improve navigation performance of precision guided missile under jamming conditions. First of all, precision missiles by GPS positioning such as SLAM-ER and JDAM were investigated. Also, the azimuth cutoff angle of satellites for usable navigation under jamming signals was analyzed by experimental tests. As a result, we found that azimuth cutoff angle under 140 degree can help ensure continuous GPS reception under the missile guidance.

Performance analysis of FH/CPFSK system with the thermal noise and the partial-band noise jamming on the rayleigh fading channel (레일리 페이딩 채널에서 열잡음과 부분대역 잡음재밍을 고려한 FH/CPFSK 시스템의 성능 분석)

  • 양정모;박진수
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.6
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    • pp.42-51
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    • 1996
  • Performance analysis of FH/CPFSK system with liiter-discriminator detection and integrate-dump post-detection filtering under the thermal noise and the partial-band noise jamming on the rayleigh fading channel have been analyzed. The thermal noise and partial-band noise jamming, rayleigh fading, intersymbol interference for all eight of the possible adjacent bit data patterns, and FM noise click for evaluating systems have been considered. Also optimum parameters to improve performance of FH/CPFSK system have been obtained and validities for AMPS and CDMA system of land-mobile-communication system through computer simulation have been proved.

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Increasing Secrecy Capacity via Joint Design of Cooperative Beamforming and Jamming

  • Guan, Xinrong;Cai, Yueming;Yang, Weiwei;Cheng, Yunpeng;Hu, Junquan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.4
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    • pp.1041-1062
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    • 2012
  • In this paper, we propose a hybrid cooperative scheme to improve the secrecy rate for a cooperative network in presence of multiple relays. Each relay node transmits the mixed signal consisting of weighted source signal and intentional noise. The problem of power allocation, the joint design of beamforming and jamming weights are investigated, and an iterative scheme is proposed. It is demonstrated by the numerical results that the proposed hybrid scheme further improves secrecy rate, as compared to traditional cooperative schemes.

Evaluation of Vulnerability to Jamming Signal of WiBro System (와이브로 시스템의 방해 신호 취약성 분석)

  • Baek, Seung-Min;Park, Su-Won;Choi, Yong-Hoon;Chung, Young-Uk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.6A
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    • pp.529-537
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    • 2010
  • Because the location of the pilot sub-carriers of WiBro system ca be acquired from the specification, jamming signals can easily attack them. It causes more serious error than the attack to the data sub-carriers. Therefore, for military application of the WiBro system, frequency hopping or encryption of location of pilot sub-carriers is needed.